I'm Lvl 263 CWA and I've been running with 12 Infiltrators, 3 Greek tanks (sometimes artillery), 4 Bazookas, and some shooters, 6 Fighters and 1 Bomber. I don't bother luring out defenders other than having to deal with Generals. That's what the tanks do, keep them occupied if necessary. It just doesn't matter what the base setup is generally. Fighters sole job is to take out defenders before they get to the Infiltrators. I have been 5 starring every Atomic, most CWA, and some Space Age though bases with high air-defense or a rocket arsenal are the only ones I find problematic. If your fighters go down, the infiltrators do get taken out quickly. The real nuisance is the bazookas triggering traps, because if they get lost, I run out of time clearing the other buildings. I should mention no tactics used unless absolutely necessary and General dropped at the end to cleat buildings.
With my drop and go strategy I do lose 8-10 infiltrators sometimes though not always. I will typically lose a fighter as well. I only hit bases with at least 4k oil, and I have a +54% All resources looted at the museum so the math always works out well even if that happens. My best is 19k oil won, with 1k oil retrain cost.
Question for others with this strategy, now with Bastions I think this composition will not work as well. If people setup the bastions right, infiltrators will spend a bunch of time breaking through to get to the defensive building, there is no other way in if designed right. I haven't seen any bases yet that pose a problem but I would be interested in getting other people's thoughts whether that will make this composition less viable.